The invention relates to a spacer or valved chamber for delivering aerosol medication from an MDI canister in a dispenser (xe2x80x9cbootxe2x80x9d) supplied by the manufacturer to a patient, through a hand-held chamber operated by the patient, and particularly to an inexpensive collapsible, disposable valved chamber.
MDI drug canisters, which have been used since 1956, are sold with a xe2x80x9cbootxe2x80x9d that includes an actuator, a nozzle, and a mouthpiece. The patient can self-administer the MDI drug using the boot alone; however, the patient must place the mouthpiece of the boot in or near his/her mouth and inhale exactly when the MDI canister is actuated. This is difficult for some patients. Therefore, various suppliers have provided valved chambers that can be used in conjunction with an MDI boot. Such valved chambers may improve drug delivery by reducing the oropharyngeal deposition of the aerosol drug and by making synchronization of the MDI canister actuation with inhalation of the ejected medication less critical.
A commonly used valved chamber of this type is manufactured by Monaghan Medical Corporation, marketed under the trademark xe2x80x9cAEROCHAMBERxe2x80x9d, and refers to U.S. Pat. Nos. 4,470,412 and 5,012,803. Another similar valved chamber of this type is marketed under the trademark xe2x80x9cOPTICHAMBERxe2x80x9d, described in U.S. Pat. No. 5,385,140 (Smith).
The prior AEROCHAMBER device utilizes only an inhalation valve, so the patient must exhale before placing the device in his/her mouth. That presents a significant problem because it is difficult for many patients to initially perform the required sequence of (1) exhaling, (2) then immediately placing the chamber mouthpiece in his/her mouth, (3) then actuating the MDI canister to inject a medication plume into the valved chamber, and (4) then taking a slow deep breath and holding his/her breath for a few seconds. The prior OPTICHAMBER device provides both an inhalation valve and an exhalation valve, so that device need not be removed from the patient""s mouth in order to use it.
A problem of the prior art is that the prior valved chamber devices are far too expensive to be considered disposable, and/or they are not at all collapsible or are insufficiently collapsible to be carried conveniently in a briefcase, vest pocket, or the like. U.S. Pat. Nos. 4,637,528 and 4,641,644 disclose aerosol inhalation devices that are partly collapsible, but not to a generally thin, flat configuration. U.S. Pat. No. 4,953,545 discloses a chamber that is disposable but not collapsible.
The retail cost of prior valved chambers described above typically is as much as nearly $40.00. This cost may be acceptable to patients having chronic conditions that require frequent use of MDI inhaler medication for a long period of time, provided the patients are willing to frequently clean such MDI inhalers. However, many patients need MDI inhaler medications for only a short period of time, in which case the high cost of the prior art valved chambers is very unsatisfactory, especially if a substantially lower cost alternative were available.
Thus, there is an unmet need for an improved valved chamber device which avoids the above mentioned problems of the prior art and provides a portable, light, reliable, inexpensive, disposable, collapsible, easy-to-use valved chamber for use with MDI inhalers. There also is an unmet need for an improved valved chamber device which is sufficiently inexpensive that it can be used as a disposable diagnostic dosing aid, temporary medication delivery aid, or teaching aid for instructing patients in the use of valved chamber devices. There is a further need for such a valved chamber which can be xe2x80x9cpopped upxe2x80x9d from the collapsed configuration into an expanded configuration, and which retains the expanded configuration unless it is manually pressed back into the collapsed configuration.
Accordingly, it is an object of the invention to provide an inexpensive, disposable, collapsible valved chamber for delivering MDI medications or vaccines.
It is another object of the invention to provide an inexpensive, disposable valved chamber which is collapsible to a flat configuration.
It is another object of the invention to provide an easily manufacturable valved chamber which is collapsible to a flat configuration.
It is another object of the invention to provide a valved chamber which is sufficiently inexpensive that it can be used as a discardable diagnostic dosing aid, temporary medication delivery aid, or training aid by means of which a health care provider can demonstrate proper techniques for using a permanent valved chamber.
It is another object of the invention to provide a valved chamber which can pop up from a collapsed configuration to an expanded configuration ready for use.
It is another object of the invention to provide a valved chamber which can pop up from a collapsed configuration to an expanded configuration ready for use and retain the expanded configuration.
It is another object of the invention to provide a valved chamber which can be xe2x80x9cpopped upxe2x80x9d or erected from a collapsed configuration by a user with a minimal amount of effort.
It is another object of the invention to reduce the amount of effort required of a user to erect a collapsible/expandable valved chamber.
Briefly described, and in accordance with one embodiment thereof, the invention provides an elongated housing for receiving a plume of medication particles ejected by an MDI inhaler, having a medication inlet end and a medication outlet end, a mouthpiece at the medication outlet end, a one-way inhalation valve disposed between the mouthpiece and a first volume bounded by the housing for allowing flow of gas from the first volume to the mouthpiece, an exhalation port or valve disposed in the mouthpiece for allowing flow of gas from within the mouthpiece to ambient atmosphere outside of the apparatus, an adapter connected to the medication inlet end for receiving and stabilizing a mouthpiece of the MDI inhaler, wherein the one-way inhalation valve includes an inhalation membrane adjacent to a valve seat. An exhalation by a patient into the mouthpiece presses the inhalation membrane against the valve seat to prevent flow of exhaled gas from the mouthpiece into the first volume, causing the exhaled gas to flow from the mouthpiece through the exhalation port or valve. An inhalation from the mouthpiece by the patient causes the inhalation membrane to swing away from the valve seat and allow passage of air from the volume into the mouthpiece.